TUSCALOOSA, Ala. (AP) — Three married couples killed in the crash of a small airplane in Alabama all lived in the university town of Oxford, Mississippi, where city flags were lowered Monday as residents grappled with the loss of so many lives at one time.

“I don’t even know what to say,” said Oxford Mayor George “Pat” Patterson.

Friends, relatives and officials identified the dead as dentists Jason Farese and Lea Farese; dentist Michael Perry and his wife, Kim Perry, a nurse practitioner at the University of Mississippi; and dentist Austin Poole and his wife, Angie Poole. The three couples were parents of 11 children total.

The Oxford Eagle reported that the plane went down while the six were returning home to the city of 19,000 following a dental seminar in central Florida.

“It’s just a sad day,” said Patterson, who knew all the victims. “The families were invested with their time and talents in the community.”

The Federal Aviation Administration said a twin-engine Piper carrying the six left Kissimmee, Florida, and crashed while trying to land in Tuscaloosa on Sunday morning. Police there said the aircraft had engine problems, but further details were not available.

It wasn’t clear whether a stop was planned in Alabama before the trouble occurred.

National Transportation Safety Board investigator Heidi Kemner, speaking Monday to reporters during a briefing on the crash, said she had located the pilot’s log book and would try to locate aircraft maintenance records.

Jason Farese was a private pilot first certified in 2004, and the plane was registered to a company that shares an address with his Oxford dental office, FAA records showed. The practice’s website said both Jason and Lea Farese were graduates of the Ole Miss dentistry school and had three children.

Michael Perry also attended the Mississippi dentistry school and served as a mentor to first- and second-year dental students. Kim Perry was certified as a women’s and family nurse practitioner and had worked for the university’s student health center since 2007. The couple had three children.

The parents of five children, Austin and Angie Poole lived in Oxford. He commuted about 60 miles to a dental office in Clarksdale, where Mayor Bill Luckett, an attorney, said he had known the couple for years.

“Austin and Angie have both been clients of mine as a lawyer and have been friends of mine,” Luckett told WREG-TV. Luckett also was related to Jason Farese by a previous marriage.